TM89 (U-Turn) is found in Canalave City in DPPt. Requiring Surf, head to the canal and Surf south, there you will find the TM.
TM89 can also be purchased at the Veilstone Game Corner for 6000C (or 120000 Pokedollars).
U-turn is found by going to the left side of Canalave city, and Surfing downward. You will find it hidden in a small area.
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